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Genetic studies indicate that protein homeostasis is a major contributor to metazoan longevity (1). Collapse of protein homeostasis results in protein misfolding cascades and the accumulation of insoluble protein fibrils [...]

Culture experiments were used to assess the applicability of Emiliania huxleyi coccolith morphology as a palaeo-sea-surface salinity (SSS) proxy. Coccolith morphology was dependent on salinity over a range reflecting present day marine conditions; both coccolith size and the number of coccolith elements increased linearly with increasing salinity. Using regression analysis, the effect of salinity on coccolith morphology was compared to those previously observed in sediment core-top and plankton data. No significant differences were found between the slopes of these data, suggesting that salinity is the primary control on E. huxleyi coccolith size and element number in the ocean. However, the intercepts of the culture data were significantly higher. A combination of experimental and literature analysis indicated that temperature and nutrients were unlikely to be the causes of this discrepancy. Literature analysis also highlighted that coccolith size data from marginal environments displayed different intercepts to those from the open-ocean data. This suggests that discrete morphotypes exist in these marginal locations. We, therefore, recommend that the original E. huxleyi coccolith morphology palaeo-SSS transfer function requires further evaluation before being routinely applied.

Few studies have studied the food supply to larval fish in the Irish Sea; thus, we have assessed the full prey-field available to larval fish, ranging from protozoa to copepods. Specifically we assessed if fish larvae feed on protozoa, as suggested by others, and if densities of the protozoa and the appropriate size of metazoan prey were previously underestimated. By examining the gut-contents of fish larvae, the prey available to them, and the potential accessibility of prey to fish, we develop a simple food web, presented as a box-model. By doing so, we indicate that the lack of focus on small metazoa and protozoa has underestimated the food available to fish larvae; without these, we might have concluded that prey levels were too low to support the growth of the larval fish assemblage. Our methods were as follows. Sampling was at two sites, off the Isle of Man, with distinct physical and biological structures, soon after fish spawning: the southwest coast, where many species occur in spring-summer (23 April; 6, 19 May; 1, 22 June; 12 July) and the east coast, where only herring larvae occur in September-November (12, 28 October). Microplankton (15-200 [micro]m), mesozooplankton, and larval fish were collected at 1, 15, and 25 m: microplankton with 1.5 L bottles and a 64 [micro]m-mesh net; mesozooplankton and larval fish with a Gulf VII high-speed sampler (280 [micro]m mesh). The 64 [micro]m mesh net, mounted on the Gulf VII, provided simultaneous hauls. Fixed samples were evaluated to determine species composition, abundance, and biomass. Larval fish diet was determined from fish collected by short net hauls: fixed guts were examined and prey, including protozoa, analysed. Using physical data as a guide, plankton data were integrated through the water column to determine standing stocks. Size-based food availability to larval fish was estimated from the gut contents. The role of protozoa was examined, assuming that they are digested at the same rate as metazoan and if they are digested 2.5-10 times faster; increased digestion rates indicated that they contributed substantially to the larval fish diet., Introduction As larval fish mortality can be attributed to starvation (Leggett and Deblois 1994), their feeding has been extensively studied (May 1974; Blaxter and Ehrlich 1974; Cushing 1990; Heath 1992). [...]

The combined effect of temperature and food concentration on the growth rate, cell volume, and production of the freshwater ciliate Urotricha farcta was investigated in laboratory batch cultures. Experimental temperatures ranged from 9 to 25[degrees]C and food levels ranged from 0.1 to 4.4 [micro]g C [ml.sup.-1]. The ciliates were fed the small cryptophyte Cryptomonas sp. The combined effect of temperature and food on growth and cell volume resulted in negative production rates at high temperatures and low to moderate food supply. Three main changes were observed in the shape of the numerical response (growth vs. food concentration) of U. farcta with temperature: change in the threshold level, where population net growth rates are zero; change in the initial slope of the numerical response curve; and change in maximum growth rate ([[micro].sub.max]). The threshold food concentration and [[micro].sub.max] were shifted up at the highest temperatures. The threshold level was also higher at the lowest experimental temperature. The initial slope of the numerical response curve was several-fold lower at both high and low temperatures. The analysis suggests that temperature altered the numerical response so that the species shifted from being adapted to low food concentrations at moderate temperatures to requiring, and potentially thriving at, high food concentrations at the temperature extremes. These findings support and extend conclusions previously obtained for metazooplankton and indicate that changes as small as 3[degrees]C could alter the role of protozoa in planktonic food webs.

We examined the response of diatoms to naturally experienced temperatures and tested these hypotheses: (1) diatoms follow the rule that organism size decreases with increasing temperature; (2) diatom growth rate follows a [Q.sub.10]-like response; (3) diatom carbon (C) and nitrogen (N) content per unit volume (V) decrease with increasing size, and changes in temperature affect this relationship; and (4) diatom C: V is the same as that of other phytoplankton. We also present, as predictive equations, relationships between (1) growth rate, temperature, and size; (2) C content and V; and (3) N content and V. Eight diatoms and two flagellates were acclimated for approximately five generations and grown for approximately five more generations at five temperatures (9-25 [degrees] C) on a 14:10 light: dark cycle at ~50 [micro]mol photons [m.sup.-2] [s.sub.-1]. Growth rate, cell V, and C and N content per cell were measured; relationships between these parameters and temperature were determined. For five diatoms and both flagellates, cell V decreased with increasing temperature; cells decrease by ~4% of their mean V per [degrees] C. Growth rate appeared to increase linearly with temperature in all cases. The literature suggests that a linear response is the rule, not the exception. Temperature did not significantly affect C or N per V of diatom species. When all diatoms were considered, both C and N per V decreased with increasing cell size; our data support the argument that diatoms differ from other protists in this respect, but the difference is less pronounced than stated in previous reports.

A time correlated single-photon counting and femtosecond Ti: sapphire laser excitation is used to study the one- and two-photon induced fluorescence anisotropy decay of rhodamine 6G (R6G) during polymerization of tetramethyl orthosilicate (TMOS) approaching the sol-to-gel transition. It is reported that a biexponential decay of fluorescence anisotropy is observed at all times.